Now that we appear to be at a sustainable 300 MK/sec (which I could hardly believe at first :-), is there any chance we could be attacking the 56-bit DES key next? DES is rumoured to be faster than RC5; also, there are likely to be optimized assembler versions out there already. We could also make better use of 64-bit architectures, since DES uses 64-bit blocks. However (and this is a very big however), that's still a keyspace of 7.2*10^16 keys to search. Assuming 10^9 keys/second (three times our current speed, which may be attainable with a good DES implementation) that's still a bit over two years; too long by a factor of 10 or so. Soo.... How fast are current DES implementations? People could try des.c from the ssh distribution as a starting point. How much more computing power could we bring online? Do people have optimized DES for Alpha, UltraSparc, HP 8000 and all the other nifty 64-bit architectures? Does it make sense to use MMX or equivalent for DES? -- Thomas Koenig, Thomas.Koenig@ciw.uni-karlsruhe.de, ig25@dkauni2.bitnet. The joy of engineering is to find a straight line on a double logarithmic diagram.